People who have higher intakes of dietary vitamin K decrease their risk of developing non-Hodgkin’s lymphoma, according to researchers from the Mayo Comprehensive Cancer Center.

To explore the association between vitamin K and risk for non-Hodgkin’s lymphoma, a research team led by James Cerhan, MD, PhD, a cancer epidemiologist, recruited 603 patients with newly diagnosed non-Hodgkin lymphomas and 1,007 matched cancer-free individuals. Participants in each group completed food questionnaires about their usual intake of more than 120 food items 2 years prior to their diagnosis or enrollment into the study. Vitamin K intake was estimated from data collected on use of a variety of supplements.

Researchers reported that the risk of developing non-Hodgkin’s lymphoma was approximately 45% lower for participants who had vitamin K intakes in the top quartile compared to participants who had intakes in the bottom quartiles. Even after accounting for age, sex, education, obesity, smoking, alcohol use, and intake of foods with high amounts of antioxidants, the association between vitamin K and non-Hodgkin’s lymphoma risk remained.

However, the study revealed that while the use of vitamin K supplements did protect against non-Hodgkin’s lymphoma, the association reached a point where the highest intake offered no reduction in risk. “The significant of this finding is unclear,” Dr. Cerhan explained, “but suggests that taking high doses of supplements is unlikely to be helpful.”

“Whether the protective effect we observed is due to vitamin K intake, or some other dietary or lifestyle exposure, cannot be definitely assessed in this study,” said Dr. Cerhan. “But these findings add to a lot of other data that support a diet that included plenty of green leafy vegetables in order to prevent many cancers as well as other diseases.”

The findings were presented at the Annual Meeting of the American Association for Cancer Research.